KANSAS CITY, Mo. (AP) Andy Reid addressed the Kansas City Chiefs in a jubilant locker room dressed from head-to-toe in a Santa Claus suit, which not only fit him perfectly but was also perfectly fitting.

The Chiefs had just given their fans quite a present.

Alex Smith threw for 304 yards and a touchdown in another steady performance, Kareem Hunt ran for 91 yards and a score, and the Chiefs beat the Miami Dolphins 29-13 on Sunday to clinch back-to-back AFC West titles for the first time in franchise history.

"Just phenomenal," Reid said, likely smiling beneath his fluffy white beard. "But we're not going to sit on this. We're not done yet. We're going to enjoy the holiday and get right back at it."

Tyreek Hill had six catches for 109 yards, and Harrison Butker converted five field goals, as the Chiefs (9-6) dashed what faint postseason hope the Dolphins (6-9) still harbored.

Cutler threw for 286 yards and a touchdown, but a big chunk of that came on a 65-yard toss to Jakeem Grant late in the first half. Otherwise, Miami went 0 for 8 on third down and struggled against a Chiefs defense that has been stingy and opportunistic the past two weeks.

That's coincided with the return of Marcus Peters from his disciplinary suspension.

The Chiefs' star cornerback had two interceptions and forced a fumble against the Chargers last week, a win that pushed them to the brink of the playoffs. He recovered a fumble and forced another on Sunday, giving Peters a hand in five turnovers the past two weeks.

"He's always around the ball," said Chiefs linebacker Derrick Johnson, who forced the first fumble. "Marcus is always playing with fire, this whole year."

Both turnovers led to points, but they weren't the Dolphins' only costly miscues.

They also were nailed for defensive holding four times, all of which came on three scoring drives for Kansas City. And the Dolphins inability to get off the field on third down, after holding opponents to 8 for 39 the past two games, was similarly deflating.

"Got in a couple situations that we couldn't use some of the things that we had planned," Miami coach Adam Gase said. "We just need to find a way to be consistent and get them off the field."

Still, the Dolphins had the ball trailing 17-13 late in the first half, the outcome and their longshot playoff hopes were still in the balance. But they soon went three-and-out and the Chiefs added a field goal to make it 20-13 at the break, then another to start the second half.

Even when the Dolphins made a crucial stop on fourth down to get the ball back later in the third quarter, they squandered the opportunity. Peters stripped Kenny Stills to give the Chiefs the ball, and Butker hit his fourth chip-shot field goal for a 26-13 lead with 12:19 to go.

That gave a sparse crowd that turned out on Christmas Eve, braving slick roads from an overnight snowfall and frigid wind chills at kickoff, plenty of time to celebrate a division title.

Turn their thoughts toward a home playoff game in the new year, too.

"It's a great feeling," Hunt said. "We've got these fans that are going to go crazy for the playoff game, and we get to play in Arrowhead Stadium one more time."

FROZEN FIELD

There was no tarp on the field overnight, so a crew of workers used shovels to remove about an inch of snow by hand. The footing turned out to be fine, but Smith thought the cold weather gave Kansas City an advantage. "We have a lot of experience playing in cold weather," he said. "All the little things, the snaps, they're that much harder, and I think all the reps do help."

STATS AND STREAKS

Chiefs TE Travis Kelce had four catches for 47 yards and a score , and has a catch in 63 straight games. ... Chiefs coach Andy Reid improved to 5-1 against Miami. ... Dolphins WR Jarvis Landry had five catches for 51 yards, giving him a league-best 103 catches this season. ... The Dolphins had won seven of their last 10 against Kansas City. Their last loss at Arrowhead Stadium was in 2002.